Blood vascular system of the sea cucumber,Stichopus moebii (original) (raw)
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Non-respiratory blood vessels in Latimeria gill filaments
Philosophical Transactions of the Royal Society B: Biological Sciences, 1998
A study of the blood pathways within the gills of Latimeria has been carried out using light and transmission electron microscopy. Clear evidence has been found for the presence of a secondary non–respiratory circulation in addition to the well–established respiratory pathway through the gill lamellae. All essential components of this system have been observed and have the same relationships and basic structure as comparable secondary systems in actinopterygian and elasmobranch fishes. These include a central venous sinus (CVS), arterio–venous anastomoses (AVAs) and central filament arteries (CFAs). AVAs connect both arterial vessels of the primary circulation and CFAs of the secondary circulation to the CVS. The latter contained many red blood cells. The presence of this secondary circulation in Latimeria gills contrasts with the situation in the gills of the three living genera of lungfishes where a system possessing the essential features of the tetrapod lymphatic vessel system h...
Studies on the fine structure of invertebrate blood vessels
Cell and Tissue Research, 1976
The position, structure and function of the valves within the lateral sinus of the medical leech, Hirudo medicinalis, are described on the basis of vital, light-and electron microscopy, In this species the valvular apparatus consists of multiple elongated fir cone-shaped fibrous villi surrounding the orifices of the latero-lateral and latero-dorsal vessel like a tentacular crest. Each villus is covered by a thin sheet of a continuous endothelium. The valves prevent the backflow of hemolymph during systolic contraction of the lateral sinus.
Russian Journal of Marine Biology, 2004
The ultrastructure of the wall of the main blood vessels of the phoronid Phoronopsis harmeri is described. The walls of the lophophoral and left lateral vessels consist of myoepithelial cells of the coelomic lining (peritoneal cells), a thin basal lamina, and an incomplete endothelial lining. In the head region of the body, the wall of the medial vessel consists of myoepithelial cells of the coelomic lining (peritoneal cells), a basal lamina, and true muscular endothelial cells. The anterior part of the medial vessel functions as the heart. In the anterior part of the body, the medial vessel wall consists of five layers: the external nonmuscular coelothelium, a layer of the extracellular matrix, the internal muscular coelothelium, an internal layer of the extracellular matrix, and an incomplete endothelial lining. The complicated structure of the medial vessel wall may be explained by the superimposition of the lateral mesentery on the ordinary vessel wall.
Peripheral vascular apparatus in some aquatic oligochaetes with special references to haplotaxids
Hydrobiologia, 1996
The organization of the peripheral vascular apparatus in two haplotaxids has been studied and compared with that of other microdriles. Considerable differences in the circulatory systems of Pelodrilus leruthi and Haplotaxis gordioides, especially in relationships to the body wall muscle fibers, separate and distinguish the two animals. Different organizations of the peripheral apparatus that can be observed in these microdriles are: in the first species, capillary vessels have no contact with the body wall; in the second species, capillaries extend between the longitudinal muscle fibers until they reach the body surface, thus approaching the situation in megadriles where circulation can become intraepithelial.
2005
The vascular organisation of the branchial basket was examined in two Tetraodontiform fishes; the three-barred porcupinefish, Dicotylichthys punctulatus and the banded toadfish, Marylina pleurosticta by scanning electron microscopy of vascular casts and standard histological approaches. In D. punctulatus, interarterial anastomoses (iaas) originated at high densities from the efferent filamental and branchial arteries, subsequently re-anastomosing to form progressively larger secondary vessels. Small branches of this system entered the filament body, where it was interspersed between the intrafilamental vessels. Large-bore secondary vessels ran parallel with the efferent branchial arteries, and were found to constitute an additional arterio-arterial pathway, in that these vessels exited the branchial basket in company with the mandibular, the carotid and the afferent and efferent branchial arteries, from where they gave rise to capillary beds after exit. Secondary vessels were not found to supply filament muscle; rather these tissues were supplied by single specialised vessels running in parallel between the efferent and afferent branchial arteries in both species examined. Although the branchial vascular anatomy was generally fairly similar for the two species examined, iaas were not found to originate from any branchial component in the banded toadfish, M. pleurosticta, which instead showed a moderate frequency of iaas on other vessels in the cephalic region. It is proposed that four independent vascular pathways may be present within the teleostean gill filament, the conventional arterio-arterial pathway across the respiratory lamellae; an arterio-arterial system of secondary vessels supplying the filament and non-branchial tissues; a system of vessels supplying the filament musculature; and the intrafilamental vessels (central venous sinus). The present study demonstrates that phylogenetic differences in the arrangement of the branchial vascular system occur between species of the same taxon.
Gills as Possible Accessory Circulatory Pumps inLimulus polyphemus
The Biological Bulletin, 1989
Heart electrical activity (ECGs), gill closer muscle potentials (EMGs), and blood pressures in the heart and the branchiocardiac canals, were measured in adult horseshoe crabs (Limuluspolyphemus) during var ious activities. During ventilation, hyperventilation, and swimming, large transient increases in pressures (10â€"35 cm H2O) occur in the branchiocardiac canals, which carry blood from the gills to the heart. These pulses of positive pressure are related to, and apparently caused by, gill plate closing. During quiescent periods, with no ventilatory activity, there are no pressure pulses in the canals, but the pressure is still greater than zero. We found covariation of heart and ventilation rates during intermittent ventilation, hyperventilation, gill cleaning, and swimming, as well as evidence of transient periods of phasic coordination. The heart appears to be weakly entrained to the gill rhythm by phasic cardioregulatory nerve input. The preferred phase of heartbeats, with re spect to gill rhythm, was 0.5, or 180 degrees out of phase. In some animals, intra-cardiac pressures were enhanced when the heart and gill rhythms were entrained. We sug gest that rhythmic movements of the gill plates enhance the flow oflow pressure blood returning from the body to the heart. Thus, ventilatory appendage movements may constitute an accessory blood pumping mechanism in Limulus.
The microvasculature of the elasmobranch gill
Cell And Tissue Research, 1980
Corrosion replicas were made of the gill vasculature of the spiny dogfish shark (S. acanthias) and little skate (R. erinacea) by methyl methacrylate perfusion via the ventral or dorsal aorta at 2.0-5.3 kPa. After tissue maceration the replicas were examined by light and scanning electron microscopy. In both species 3 vascular pathways were found: (1) the major pathway subserving the respiratory function of the gill, consisting of the afferent filamental artery which feeds into a medial afferent sinus (MA) from which arise the prelamellar arterioles (AL) leading to the lamellae, the postlamellar arterioles and efferent filamental artery (EA); (2) a nutrient circulation arising from the EA, supplying oxygenated blood to the filamental tissue, and anastomosing with the interlamellar vessels (IL); (3) a collateral circulation consisting of ILs which drain through channels interdigitating with the ALs and which then form a collateral reticulum, beneath the water channel epithelium, with vessels from the adjacent filaments. In the dogfish; small prelamellar arteriovenous anastomoses (PA) connect the MAs to the ILs with the same frequency as the ALs. PAs have not been found in the skate, but the efferent nutrient circulation is much more extensively developed. Many similarities exist between the elasmobranchs and teleosts in regard to the microvascular organization of the gill.